Effect of Gelatin on Characteristics of an Enzymatically-Gellable Alginate Hydrogel Scaffold for Cartilage Tissue Engineering

Background and Aim: Alginate as a natural polysaccharide is widelyused in biomedical applications due to its excellent biocompatibilityand biodegradability. However, this material lacks cellular interactionsand suffers from poor cell adhesion. In this work, the phenolic moietieswere introduced into alginate to form enzymatically-gellable alginate(Alg-ph) for mechanical strength improvement in culture medium andgelatin (Gel) was also used to enhance the cellular adhesion properties.In order to prevent gelatin from moving the scaffold, this compound wasalso phenolized (Gel-ph).Methods: Tyramine and EDC were used to add phenolic groups of thealginate and gelatin. Hydrogels of Alg-ph, Alg-ph + Gel and Alg-ph +Gel-ph were prepared using Horseradish peroxidase (HRP) and H2O2 andanalyzed by UV, microstructure (SEM), mechanical strength, degradationby lysozyme enzyme, swelling ratio, gelation time and cell culturetest. Chondrocyte cells were expanded in low glucose Modified Eaglemaintained at 37˚C with 5% CO2 in the incubator. Media containingChondrocyte cells at 1×106 cells/mL were mixed with all hydrogels atfinal concentrations of 1.5% (w/v).Results: Alg-ph and Gel-ph showed absorption at 275 nm wavelengths,indicating that phenolic groups were successfully introduced on thecompounds. By adding gelatin to Alg-ph, the swelling and strains ofhydrogel increased 3.5 and 5-fold, respectively. Also, with the additionof Gel-ph compared to gelatin, swelling increased about 5.5 times andthe breaking strain was reduced 0.8 times due to the porosity createdin the hydrogel structure. In the analysis of degradation, Alg-ph + Geland Alg-ph + Gel-ph hydrogels were 1.6 and 2.1 times higher thanAlg-ph, respectively. SEM images showed uniform pore sizes in Alg-ph+Gel-ph samples. Evaluation of chondrocyte cell proliferation within thehydrogels for all three types of hydrogels at the same seeding densityrevealed that the cells proliferated approximately 4 times in the Alg-ph +Gel-ph hydrogels, the value of which was 3.7 times for the Alg-ph + Gelhydrogels, after 21 days.Conclusion: Characteristics of hydrogels such as swelling, mechanicalstrength and degradation could be controlled by introducing the phgroups to alginate and gelatin. According to the observed results, Alg-ph + Gel-ph revealed an appropriate scaffold property for use in soft tissueengineering, especially for cartilage tissue.

کلیدواژه ها:

Scaffold ، Alginate ، Gelatin ، Cartilage tissue engineering